fix(ui): keep timeline preview tooltip interactive

Allow pointer interaction with the message preview tooltip and delay hover dismissal so users can move from the timeline segment onto the preview to copy or delete.

packages/ui/src/components/message-timeline.tsx

@@ -276,6 +276,7 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
   const [tooltipSize, setTooltipSize] = createSignal<{ width: number; height: number }>({ width: 360, height: 420 })
   const [tooltipElement, setTooltipElement] = createSignal<HTMLDivElement | null>(null)
   let hoverTimer: number | null = null
+  let closeTimer: number | null = null
   const showTools = () => props.showToolSegments ?? true
  
   const registerButtonRef = (segmentId: string, element: HTMLButtonElement | null) => {
@@ -292,10 +293,30 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
       hoverTimer = null
     }
   }
+
+  const clearCloseTimer = () => {
+    if (closeTimer !== null && typeof window !== "undefined") {
+      window.clearTimeout(closeTimer)
+      closeTimer = null
+    }
+  }
+
+  const scheduleClose = () => {
+    if (typeof window === "undefined") return
+    clearHoverTimer()
+    clearCloseTimer()
+    // Small delay so the pointer can travel from the segment to the tooltip.
+    closeTimer = window.setTimeout(() => {
+      closeTimer = null
+      setHoveredSegment(null)
+      setHoverAnchorRect(null)
+    }, 160)
+  }
  
   const handleMouseEnter = (segment: TimelineSegment, event: MouseEvent) => {
     if (typeof window === "undefined") return
     clearHoverTimer()
+    clearCloseTimer()
     const target = event.currentTarget as HTMLButtonElement
     hoverTimer = window.setTimeout(() => {
       const rect = target.getBoundingClientRect()
@@ -305,9 +326,7 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
   }
 
   const handleMouseLeave = () => {
-    clearHoverTimer()
-    setHoveredSegment(null)
-    setHoverAnchorRect(null)
+    scheduleClose()
   }
  
   createEffect(() => {
@@ -326,7 +345,10 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
     setTooltipCoords({ top: clampedTop, left: clampedLeft })
   })
 
-  onCleanup(() => clearHoverTimer())
+  onCleanup(() => {
+    clearHoverTimer()
+    clearCloseTimer()
+  })
 
   createEffect(() => {
     const activeId = props.activeMessageId
@@ -432,6 +454,8 @@ const MessageTimeline: Component<MessageTimelineProps> = (props) => {
               ref={(element) => setTooltipElement(element)}
               class="message-timeline-tooltip"
               style={{ top: `${tooltipCoords().top}px`, left: `${tooltipCoords().left}px` }}
+              onMouseEnter={() => clearCloseTimer()}
+              onMouseLeave={() => scheduleClose()}
             >
               <MessagePreview
                 messageId={data().messageId}

packages/ui/src/styles/messaging/message-timeline.css

@@ -211,7 +211,8 @@
 .message-timeline-tooltip {
   position: fixed;
   z-index: 1000;
-  pointer-events: none;
+  /* Allow interacting with the preview (copy/delete/etc). */
+  pointer-events: auto;
 }
 
 .message-preview {